Investigation properties of liquid 3- helium by LOCV method

In this paper, by using cluster expansion under method of lowest order constraint variational, we investigate at absolute zero temperature and finite temperature energy and Helmholtz free energy of normal liquid 3- helium. We consider as a many body system up to two and three- body cluster approximation with L J, HF D-B and MDD- 2 sample central potential. Then we obtain thermodynamic quantities such as entropy, chemical potential, pressure, critical temperature, specific heat and normal boiling point by two- body cluster approximation at low densities and low temperatures. The results of numerical calculations are agreement with experimental results